Cottonmouth Intensive

The massive bluff atop which I stand is hundreds of feet high, effectively forming the southern bank of a sprawling muddy river swamp. From my vantage, I gaze to the north– peering through the leafy crowns of cherrybark and white oaks, hickories, tulip poplars and other hardwoods–looking for the swamp. I know it’s down there somewhere, I can sense it and I can even smell it… Anxious and excited as I grab my camera and load my backpack with oranges and granola, I can hardly wait to find myself in the shadows of the aquatic world below. On what is a calm, sunny day after a few chilly ones peppered with rain, I am going afield in what are ideal conditions for observing serpents.

En route from my Georgia home to the St. Louis area to see my Dad, I have detoured to visit a vast southern Illinois swamp, which, incidentally, supports one of the largest cottonmouth populations in the world. In this part of their range, cottonmouths have the interesting habit of overwintering communally in cracks and fissures associated with limestone (or sandstone) bluffs and outcrops. A number of other snakes species–including black rat snakes, blue racers, rough greensnakes, western ribbon snakes, and the remainder of southern Illinois’ viper triumvirate (copperheads and timber rattlesnakes)–share these “hibernacula” with western cottonmouths. Impressive seasonal migrations occur each spring when many thousands of cottonmouths move down slope from the bluffs to swamps and soggy bottoms where they feed (with the opposite occurring each autumn as the snakes move back to their rocky dens). Fortunately, a series of natural areas and lands within the Shawnee National Forest now protect many of these impressive snake populations.

It takes me some time to negotiate the steep slope down to the swamp. When I get there I pause to drink in some fresh air and get my bearings. A kingfisher rattles and a lovely prothonotary warbler lands near, expressing his displeasure at my presence. Fifty feet from shore a compact school of many hundreds of baby bowfin ripple the water as they repeatedly come to the surface to gulp air (Once, admiring such a school close-up while wading this very swamp, I was charged and rammed in the shin by the attendant and protective male!). Peering beneath a swampside log I spot one of my favorites, a gorgeous cave salamander smartly colored in orange-and black. (And speaking of herps sporting Halloween colors, my last visit here produced a true gem among swamp reptiles—a gorgeous western mud snake).

My enthusiasm only builds from here, and soon the snakes do indeed appear…First, a rapid-swimming yellowbelly watersnake courses by. This is one of three species of large, non-venomous watersnakes (in the genus Nerodia) that are native to southern Illinois. Then, my heart drops into my boot when I nearly trod on a very large racer, which explodes in a frenzy and snakes off at high-speed, its whip-like tail briefly slapping vegetation.

I spot the first western cottonmouth of the day slowly swimming, a few feet from and parallel to the shore. Unlike non-venomous watersnakes, when swimming cottonmouths appear very buoyant, with all of their bodies seeming to ride on top of the water (and they hold their heads well above the water). I find another cottonmouth, this one coiled on damp earth at the edge of the swamp. As I continue my stroll along the edge of this enormous slough, my field notes become punctuated with cottonmouth observations ca. every 10 minutes: “large adult looped on moss-covered rootwad in the shallows”; “lemon-tailed juvenile resting on branches two feet above the water…”; “plump male starting to emerge from hole in stump”. And then, “Ay, caramba!” I suddenly have one slithering underfoot; its wet and duckweed-speckled scales tell me that it’s just left the water.

And then, I truly locate my snake-finding rhythm, and the moccasin mother-lode. A narrow peninsula of elevated mud and sticks, the work of one or more very industrious beaver families, extends from the bank several hundred meters into the brown waters of the swamp; the fresh mud of the beaver spoil is interlaced with sticks and logs of various dimensions, upon which lie dozens of basking and foraging cottonmouths. My journey is no longer about looking for snakes. Now I am actively working to avoid stepping on them!

A common tactic employed by hungry cottonmouths is to rest in shallow, slowly-moving water that flows and trickles through logjams and debris, and many of these beaver-dam cottons do seem to be foraging. Some snake species can attribute their success in part to broad, catholic diets, and our Agkistrodon piscivorus is a good example, dining not only on fish, but on just about any other type of animal (frog, salamander, rat, snake, bird, small turtle, small alligator) that stumbles its way.

Always in pursuit of hi-quality in situ photos of snakes in their wild lairs, I strip off my backpack, gently bend my aging knees, and lie on my belly in the swamp. Now, a number of authors, even herpetologists, have described cottonmouths as “lazy and fat” and “ugly and ill-tempered”. Snake beauty is in the eye of the beholder I suppose. Sure, there are many bright colored and dramatically-patterned serpents arguably much “prettier” than the cottonmouth. But, to me, the cottonmouth is one good-looking snake.

That tightly coiled specimen on the logjam may at first resemble little more than a scaly cow pie but upon closer inspection one notices that the body is supple and there is a slight bronze cast to the neatly-keeled dorsal scales. Contrast the seeming malevolence of the elliptical pupils (a hallmark of pit vipers) with the beautiful golden irises. Scales wet, filthy with swamp plants, and a face wearing a moustache of mud doesn’t sound attractive per se—but a stout adult slinking across the swamp, head held high, could be described as magisterial. And, having observed many hundreds of cottonmouths in their native lairs during my lifetime, I can assure you there is something special, even endearing, about their personalities.

With regards to their temperament, a herpetological Mark Twain might have said “The rumors of the species’ aggression have been greatly exaggerated”. Now, cottonmouths are pit vipers, and are dangerously venomous snakes that can and will bite humans; bites from this very toxic snake are extremely serious, and have even resulted in fatalities. And, yes, they can bite underwater. It is unwise to attempt to handle, capture, kill or harass cottonmouths.

My several decades of field experience “swamp-ratting” have taught me that when encountered in the wild by humans cottonmouths are most interested in getting away and/or just being left alone. And not terribly interested in putting up a spirited defense. I can vouch for the results of the interesting (and published in peer-reviewed scientific journals) studies conducted by Dr. Whit Gibbons and his colleagues at the Savannah River Ecology Lab in South Carolina which demonstrated that–when approached or physically harassed by humans–cottonmouths typically exhibit the following defensive repertoire: First, they try to escape by crawling away or swimming off; next, they may rattle their tails, release musk from their vents, and/or gape, thus exposing the clean white lining of the mouth (hence the common name). Finally, if the above do not allow escape or dissuade the human aggressor from backing off, and the snake continues to be threatened, grabbed, poked, pressed or similarly roughly handled, well, then it may attempt to bite.

It is always a pleasure to return to southern Illinois to see my father, and to encounter scores of snakes—including vipers that swim darkwater swamps among giant cypress, as they have for millennia.